<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* 屏幕宽度小于等于768，网页背景色-》 max-width */
        @media screen and (max-width: 768px) {
            body {
                background-color: pink;
            }
        }
        /* 屏幕宽度大于等于1200，网页背景色-》 min-width */
        @media screen and (min-width: 1200px) {
            body {
                background-color: red;
            }
        }

    </style>
</head>
<body>
    
</body>
</html>